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Will Rain Damage a Window Air Conditioner?

Rain is good for the earth’s ecosystem, right? While rain is good in moderate amounts, too much of it poses several dangers, such as flooding. Because of that, you may be wondering if the rain will damage your window air conditioner.

Rain will not damage your window air conditioner. Window units are made of aluminum, metal, or copper, and their electrical components are sealed, making them impervious to moisture. However, high winds and falling trees that characterize downpours could deposit debris onto the unit, damaging it.

The rest of this article provides insights into how rain affects your window unit, why you should always wash your condenser’s filter, what actually causes damage to window ACs, and how to protect your unit from harsh weather.  

How Does Rain Affect a Window Air Conditioner?

You have probably heard that water damages the electronic components of machines. According to the Insurance Information Institute, water damage is the third leading cause of homeowner loss.

When you think of rain and your AC unit, you probably develop the feeling that rainwater could short circuit the unit. However, do not worry – let me elaborate on why rain does not damage your AC.

Window Units are Designed to Withstand Heavy Rains

Your window AC unit is designed to withstand downpours, snow, and hail. The interior components of window air conditioners are protected from precipitation. Also, their condensers comprise metals that can handle heavy rains while dehumidifying and cooling your home.

Window air conditioners also have a totally enclosed fan cooled (TEFC) compressor motors that mitigate the harmful effects of rain. Besides, your window unit has a grill for additional protection. Rainwater passes through the unit and escapes at the bottom without damaging any electrical components. That is because manufacturers cover these components using insulators. This YouTube video explains the parts of a window AC and their functions:

Rain Removes Any Debris Lodged in Window Units

Buildups of leaves, dirt, or debris around your unit’s condenser reduce your window air conditioner’s performance. Rainwater removes such buildups, improving airflow within the condenser. Alternatively, you can spray the unit with a hose to remove debris lodged in your unit.

Do not worry about getting any electrical components of your AC unit wet. Insulators prevent the possibility of a short circuit, which could damage your unit.

The Verdict: Rain Does Not Harm Your Window Unit

Rain does not damage your window air conditioner. Conversely, a little rain can have a positive impact. Rest assured that any water that enters your unit escapes down the bottom. Also, your unit has insulators that prevent short circuits. Besides, manufacturers include filters that extract any moisture that enters your AC before it reaches the cooling coils, enabling your unit to function without disruption.

The Caveat

You should wash your filter more often for a better air conditioning experience. As this post highlights, some users have experienced bad smells or AC units becoming moldy. While washing your filter, ensure the unit is tilted back, and the drain hole is free of debris. Use an antibacterial cleaner to spray the evaporator coil on the filter and let it drain for 1-2 minutes. This video explains how you can clean your unit’s filter:

What Will Damage Your Window Unit Then?

Having discarded the possibility of rain causing damage to your unit, I’ll go the extra mile to mention the events that can harm your unit. It is worth noting that storms, flooding, and corrosion can hurt your system’s performance in different ways. While some can impede airflow within AC condensers, others can damage electrical components, including the wiring system, causing a complete shutdown of your window air conditioner.


Downpours, accompanied by strong winds, carry projectiles that can hit the fan grill of your AC’s condenser. Besides, such high winds can deposit twigs, leaves, and dirt into your system- these deposits can reduce the airflow rate within your condenser. 

It is essential to always inspect your unit after a storm, locate any hidden debris, and remove it to ensure your system performs optimally. Here’s a video that highlights how debris damages your AC system:


Severe flooding could damage your unit. Deep stagnant water exceeding 38cm (15 inches) could harm the moving parts of your system. It is advisable to call a professional to inspect your unit before restarting it after experiencing localized flooding in your area. Also, install any exterior components of your unit in flood-safe areas.


Internal corrosion can hurt your air conditioner’s performance. This type of corrosion mainly arises from poor wrapping – avoid using garbage bags or plastic wraps. Poor covers enable moisture to build up, causing corrosion and rotting of internal parts while promoting mildew and mold growth. When your unit’s wires rust, the layer of iron oxide makes them poor conductors of electricity.

How Can You Protect Your Window Unit?

Now that you have gained some insight into what actually harms your AC, you’re probably wondering: “How can I protect my system then?” A more appropriate approach is being proactive – you can use weather forecasts to take preventive measures that reduce the possibility of bad weather harming your AC.

Let me suggest some of the ways you can safeguard your unit:

  • Switch off your window air conditioner. Before any inclement weather, turn off your AC’s circuit breakers. Unlike simply switching off the thermostat, turning it off at the breaker cuts the power. This intervention reduces the risks of electrical fire or damage to your unit if a power surge occurs during bad weather. A power surge could force you to replace your unit, adding to your losses after stormy weather.  
  • Tighten all bolts that hold your window unit in place. You can also use hurricane straps to secure your window air conditioner – I recommend this 2 Tie-Down Ratchet Straps from since it has a massive assembly break strength of 4535kg (10,000lbs), is robust, and sturdy.
  • Use a tarp to shield the unit from water. The cover should be tough enough to withstand strong winds – it can be made of plastic or vinyl. You can also use a plywood cage or metal around the unit to protect it from flying debris during storms.
  • Identify any possible projectiles that could hit your window AC during a storm. Outdoor furniture, grills, planters, and loose tree branches in your yard can become airborne during strong winds. You should eliminate such objects to reduce the chances of strong winds damaging your unit.
  • Inspect the system immediately after the storm. I recommend that you avoid turning your window AC on immediately after inclement weather. Instead, if you think your system has been damaged, you should call an HVAC technician to inspect your unit. It is also advisable to have a backup generator since you could have a power cut for days or weeks following a storm.
2 Tie-Down Ratchet Straps J Hooks, 2 Heavy Duty 2″ x 27′ Tie-Down Ratcheting Cargo Truck Straps Wire Hook Ends, J-Hook Ratchet Strap TieDowns

Final Thoughts

Rain is harmless to your window air conditioner. Your unit’s electrical components are sealed, making it impervious to moisture. However, you should be concerned about the following since they pose greater harm to your AC:

  • Storms
  • Flooding
  • Corrosion

To protect your AC from damage, I suggest that you:

  • Switch off your AC at the breaker
  • Secure the unit by tightening the bolt or removing it from the window
  • Cover the system using plastic, vinyl, or a cage
  • Eliminate any projectiles that could damage your unit during a storm
  • Call an HVAC technician to inspect the system after stormy weather


  • Nicole Sutton

    Nicole Sutton is an enthusiastic writer and knowledgeable contributor to She offers a plethora of knowledge to the platform, with a background in environmental science and a profound curiosity with all things connected to temperature regulation. Nicole's interesting and informative writings assist readers in making informed decisions about home heating, cooling, and climate control.

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